October 5, 2023
Yu Wang, Yi Chen, Hong T. Bui, Yujeong Bae, Soo-Hyon Phark, Andreas J. Heinrich, Christoph Wolf, Masahiro Haze, Cristina Mier, Jinkyung Kim, Deung-Jang Choi, Christopher P. Lutz
We have accomplished a groundbreaking step forward in quantum information science. In partnership with teams from Japan, Spain, and the US, we created a novel electron-spin qubit platform, assembled atom-by-atom on a surface. This breakthrough was published in the journal Science on October 5th, 2023.
Individual electron spins in solids are promising candidates for quantum science and technology, where bottom-up assembly of a quantum device with atomically precise couplings has long been envisioned. Here, we realized atom-by-atom construction, coherent operations, and readout of coupled electron-spin qubits using a scanning tunneling microscope. To enable the coherent control of “remote” qubits that are outside of the tunnel junction, we complemented each electron spin with a local magnetic field gradient from a nearby single-atom magnet. Readout was achieved by using a sensor qubit in the tunnel junction and implementing pulsed double electron spin resonance. Fast single-, two-, and three-qubit operations were thereby demonstrated in an all-electrical fashion. Our angstrom-scale qubit platform may enable quantum functionalities using electron spin arrays built atom by atom on a surface.